Anti-theft brake lock

Abstract

A hydraulic wheel brake device is provided for connection between the master cylinder and the wheel brake cylinders in the brake fluid line. The device includes a lock housing connected to a hydraulic cylinder wherein the hydraulic cylinder includes a fluid chamber having an inlet and outlet in fluid communication with the chamber. A valve seat is located over the inlet in the fluid chamber and a spring is disposed in the chamber having a steel ball held therein. A lock and rotary cam mechanism are located within the lock housing wherein rotation of the lock rotates the cam mechanism thrusting a rod connected between the rotary cam mechanism and the spring. The rod forces the spring to compress which seats the ball against the valve seat restricting fluid flow to the brakes thereby locking the fluid brake system.

What is claimed is: 
     
       1. A device for locking the brakes of a vehicle having a fluid brake system adapted to be connected in the brake fluid line between the master cylinder and at least one wheel brake cylinder, comprising: a hydraulic cylinder having a brake fluid inlet and outlet and a fluid chaxber connecting said inlet and outlet;   a valve seat within said fluid chamber in fluid communication with said inlet;   a valve element within said fluid chamber including a ball having a diameter greater than the diameter of the inlet to said fluid chamber adapted to press against said valve seat to restrict the fluid flow through said fluid chamber; and   means for pressing said ball against said valve seat including a compressible coil spring for holding said ball therein, wherein compression of said spring causes said ball to Press against said valve seat thereby restricting the fluid flow through the inlet of said hydraulic cylinder, and wherein said coil spring includes ends having a diameter greater than the diameter of said ball and a central portion for holding said ball having a diameter less than the diameter of said ball, so that upon insertion of said ball, said central portion will expand to tightly coil around and firmly hold said ball therewithin.   
     
     
       2. The device of claim 1 wherein said ball consists essentially of steel. 
     
     
       3. A device for locking the brakes of a vehicle having a fluid brake system adapted to be connected in the brake fluid line between the master cylinder and at least one wheel brake cylinder, comprising: a hydraulic cylinder having a brake fluid inlet and outlet and a fluid chamber connecting said inlet and outlet;   a valve seat within said fluid chamber in fluid communication with said inlet;   a spring disposed within said fluid chamber and being coiled so as to hold a valve element therein;   means for compressing said spring, including complementary wedge shaped male and female cams wherein rotation of said male cam thrusts said female cam toward said spring, and a piston means connected between said female cam and said spring for compressing said spring as said female is thrust toward said spring whereupon said spring causes said valve element to press against said valve seat and restrict the fluid communication between said inlet and said outlet; and   means for actuating said spring compressing means including a key operated lock mechanism connected to said male cam wherein rotation of said lock causes said male cam to rotate.   
     
     
       4. A device for locking the brakes of a vehicle having a fluid brake system adapted to be connected in the brake fluid line between the master cylinder and at least one wheel brake cylinder, comprising: a housing having a bore therein;   a hydraulic cylinder axially aligned and connected to said housing and having a brake fluid inlet and outlet and a fluid chamber connecting said inlet and outlet;   a valve seat within said fluid chamber in fluid communication with said inlet;   a spring disposed within said fluid chamber and being coiled so as to hold a valve element therein;   a rotary cam means within said elongated bore for compressing said spring including a wedge shaped male cam having tapered surfaces in communication with the oppositely tapered surfaces of a V-shaped female cam axially aligned with said male cam, wherein rotation of said male cam thrusts said female cam toward said spring, and a piston means connected between said female cam and said spring for compressing said spring; and   means in said elongated bore for actuating said rotary cam means thereby compressing said spring which causes said valve element to press against said valve seat thereby restricting the fluid communication between said inlet and said outlet.   
     
     
       5. The device of claim 4, wherein the actuating means includes a key operated lock mechanism within said elongated bore being connected to said male cam whereby rotation of said lock causes said male cam to rotate.